Available for projects · Remote

Most Shopify stores are built to launch.
I build them to last.

9+ years working exclusively on Shopify — architecture decisions that hold under scale, migrations that don't break what's already working, and performance engineering tied to real metrics.

9+ years exclusively on Shopify
3+ years with twothirds.com
5+ years with ff.md
15+ international markets configured

Real stores. Real scale.

Not demos. Not generic implementations. Projects where architecture decisions had actual consequences — on revenue, performance, and longevity.

eCommerce platform · Pharmacy · Moldova · Since 2020

ff.md

Built the online store for Moldova's largest pharmacy chain from scratch — and have been their technical partner since 2020. 30,000+ products, custom one-page checkout, fully automated backend connected via APIs. Custom theme architected and implemented for pharmaceutical-grade catalog management at scale.

Custom Theme 30k+ Products Custom Checkout API Automation Liquid
Shopify Plus · Haute Parfumerie · Luxury

edel.co

Shopify Plus redesign for an haute parfumerie brand (Eulalia de Lucia). Full theme build — homepage, product pages, collection views, mobile experience, cart — all designed to match a complete brand relaunch.

Shopify Plus Custom Theme Luxury Brand Design-Led
Custom Theme · Pharmaceutical eCommerce

dasist.ro · btonic.ro

Two pharmaceutical Shopify stores built on a custom in-house theme with exceptional performance scores — same robust architecture, adapted per brand.

Custom Theme Performance Pharmaceutical Liquid

Apps I've built and published.

Building apps means understanding both sides — what the merchant actually needs, and what makes an app good enough to survive Shopify's review process.

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Live on App Store

COS ‑ Social Share Images

Generates and customizes Open Graph images for all Shopify resource types via a template-based UI — no coding required. Built to Shopify's highest standards for performance, design, and OS 2.0 integration.

React / Polaris Node.js OS 2.0 Extensions Open Graph
View on Shopify App Store →
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UI Contribution

Schema Breadcrumbs

Built the full admin interface for this published Shopify app — structured data and breadcrumb schema injection for SEO. Delivered using Shopify Polaris and React, following Shopify's embedded app standards.

React / Polaris Shopify Embedded App Structured Data SEO
View on Shopify App Store →
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In development

VyralSocial

AI-powered Instagram content generator for Shopify merchants. Generates ready-to-post content from product and collection data using GPT-4o-mini and the Instagram Graph API.

Shopify Remix TypeScript OpenAI GPT-4o Instagram API PostgreSQL
Not published yet

Senior-level work for serious Shopify stores.

I don't take isolated tasks. I take on problems that require architectural thinking — and I stay until they're solved properly.

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Theme Architecture

OS 2.0 section/block systems, metafields, metaobjects — built to last, not to demo.

Performance Engineering

Core Web Vitals tied to real metrics. Custom build tooling, lazy loading, bfcache.

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Platform Migrations

Manual OS 1.0 → 2.0 migrations that preserve what's working. No shortcuts.

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Shopify Markets

Multi-region setup, localized content, payment methods, tax and shipping rules.

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App Development

Custom apps with React/Polaris, Node.js, built to pass Shopify's review process.

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API & Integrations

Storefront API, GraphQL, Checkout Extensions, Shopify Flow, Webhooks.

[ foto ]

Catalin Costinas
Senior Shopify Architect
Cluj-Napoca, Romania · Remote

9+ years.
One platform. Depth by design.

I've been working exclusively on Shopify since 2016. Not across five platforms. Not as a side skill. This is the only thing I do — and that depth is what separates the work.

I specialize in the layer most developers skip: architecture decisions that hold under scale, migrations that don't break what's already working, and performance engineering tied to real metrics — not just Lighthouse scores.

In practice, that means a 3-year technical partnership with twothirds.com — a B Corp-certified sustainable fashion brand with 325k+ subscribers and 14k+ Trustpilot reviews. Full manual OS 1.0 → 2.0 migration, international expansion across 15+ markets, B2B wholesale, Klaviyo integration, ongoing performance engineering.

It means building ff.md from scratch in 2020 — the online platform for Moldova's largest pharmacy chain — and staying as their technical partner ever since. 30,000+ products, custom one-page checkout, fully automated backend via APIs.

And it means building and publishing my own apps on the Shopify App Store — understanding both what merchants actually need from an app, and what it takes to pass Shopify's review process.

The clients I work with don't need someone to install a theme. They need someone who knows when the easy option will cost them six months later.

Liquid OS 2.0 Metafields / Metaobjects React / Polaris Node.js Shopify Remix Storefront API GraphQL Shopify Markets Core Web Vitals Klaviyo PostgreSQL / Prisma OpenAI API esbuild / Vite

If you're building something serious
on Shopify — let's talk.

Not looking for task-based freelancing. Looking for the kind of problem where architecture actually matters.

hello@costinas.com →